BillFitzmaurice.info

Radian wrote:Compare the terms by definition, and this age old "debate" holds no water.

Horsepower vs. Torque

Power vs. Force WTF?

They're plotted on the same chart for the exact reason that speaker cab frequency response and phase are...to provide quick visual identification of general system performance. I've never heard anyone saying, "I want more phase," or, "Screw phase, I'll take amplitude any day."

One term is a derivative of the other. Torque is a force that can impart rotation upon an object. nothing else. Power is a measure of force and distance, per unit time.

"There is no spoon."

hmm, but thats like saying 'my pa can reach 120dB'

but at what frequency?
if its all above 100hz then thats gonna hurt.

HP is the peak power, torque is more like the longterm 'useable' RMS power

We all know that you dont judge amps by their peak power rating, only RMS.

One of Drag Racing's greats, Keith Black, had a saying:

Area under the curve.

His story:

Porsche Racer, making a so-called 1000 hp. Keith's Chevy making 400 + hp was kicking it's behind on the track. Why? Area under the curve.

The Porsche makes 1000 hp at around 8000 rpm. To get to 8000 rpm you have to go through 1000, 2000, etc.

At 2000 rpm the Porsche is barely making 200 lb-ft of torque. The torque curve is very peaky - nearly flat at the beginning and peaking at high rpms.

By contrast, the Chevy had a nearly flat torque curve between 1000 and 5000 rpm, giving it a much larger area under the curve, better off the line performance and allowing the driver to shift much less to keep the curve in the "powerband", which if you know piston engines really means the "the rpm range with torque above a certain torque to weight ratio" band.

That is why except for one magazine test (which I own) which I seriously question, in every Cadillac CTS-V vs Mercedes-Benz e63 AMG test, even though everyone agrees the Merc is smoother, quieter and attracts the cops less, in real world driving, the Caddy seriously kicks it's behind.

This despite them having similar power to weight ratios and similar "tested" handling figures (figure eight, oval, etc.). If you have two excellent drivers, the acceleration figures are similar, if not, the caddy wins. This, despite the Merc having a better manual gearbox, and a much better autobox.

Again, this is because if look at the two torque curves, the Caddy has a significantly better area under the curve.

When you accelerate out of a tight corner? Torque. Especially low-speed (low rpm) torque. When one gear is two high and one gear is to low? Torque. When you're in a high speed curve and you don't want to shift because it will upset the car's "set" and force you to slow down? Torque - a nice flat torque curve especially, without significant hills and valleys.

Just like with speakers, don't believe the manufacturer's specs, which are usually (almost always) a single point on the curve - look at the WHOLE curve.

Some very unhappy, paid-nearly-twice-as-much-as-the-Caddy-to-lose-"executive"-street-races Mercedes owners out there . . .

KeithHeadley wrote:Area under the curve.

..and that would be power.


Where:
t=time in seconds
ω=rotational velocity in radians per second (rpm if you will)
Τ= torque
P=Power

Just like in RTA, the total area under the curve (the integral or sum) is the power used in the program material.

KeithHeadley wrote:Porsche Racer, making a so-called 1000 hp. Keith's Chevy making 400 + hp was kicking it's behind on the track. Why?

I can assure you with Keith Black at the helm, there were other significant factors in that comparison than just plain HP to HP. The guy was exceptional at making his cars handle too.

Well, with bikes we're more concerned (or at least, those who actually ride) with power to the rear wheel. Don't really give a crap what the specs of the engine itself is.

I don't know how this would translate to speakers. Maybe it would be like Harley guys with straight pipes making all that noise and they're barely moving. But opposite for speakers.

bzb wrote: Maybe it would be like Harley guys with straight pipes making all that noise and they're barely moving. .

I don't move much on stage...should I take up

No, you should take up drumming

yeah, I'll stick with 64 ccs and under 10 hp lol. hell yes polini kit on the ped.

KeithHeadley wrote:One of Drag Racing's greats, Keith Black, had a saying:

Area under the curve.

His story:

I think something similar might explain why on twisty roads I have no trouble keeping up with modern 4cil power houses on my 20+yr old 50-odd HP twin cylinder bike. No top end power, but torque at all revs. It handles fine and has nice traction out of tight corners. What else does one really need to enjoy those corners

sine143 wrote:yeah, I'll stick with 64 ccs and under 10 hp lol. hell yes polini kit on the ped.

64cc? Both of mine are Mallosi 50mm Big Bore kits. One on a 1987 Honda Vision/SE50P and the other on a 1994 Honda Elite/Dio/SA50. The '94 will do about 70MPH, the '87 about 45-50. Just waiting for a bit warmer weather so I can GPS them both. Mmmmm, 2-stroke goodness!

bzb wrote:No, you should take up drumming

He can't afford the required lobotomy.

Torque HP and Gearing

Had a 71 Super Beetle back in the mid 90's that would beat a new 'Vette across a large intersection where the Vette would then scream by me but could consistently beat them across the intersection.

I had ~65HP and few other mods versus the stock 45-50ish--- compare that to the Vetts.

ewetho wrote:Torque HP and Gearing

Had a 71 Super Beetle back in the mid 90's that would beat a new 'Vette across a large intersection where the Vette would then scream by me but could consistently beat them across the intersection.

I had ~65HP and few other mods versus the stock 45-50ish--- compare that to the Vetts.

I had the good fun of growing up in my pops vtwin/vdub shop where dragbikes with bug motors were the ticket. These days I get to drive his type iv ported, cammed and such '75 shopbus from time to time. Power is hydraulic in delivery..until the secondaries open up

DJPhatman wrote:

sine143 wrote:yeah, I'll stick with 64 ccs and under 10 hp lol. hell yes polini kit on the ped.

64cc? Both of mine are Mallosi 50mm Big Bore kits. One on a 1987 Honda Vision/SE50P and the other on a 1994 Honda Elite/Dio/SA50. The '94 will do about 70MPH, the '87 about 45-50. Just waiting for a bit warmer weather so I can GPS them both. Mmmmm, 2-stroke goodness!

i hit mid 50s on my setup. puch maxi with the polini kit and a proma gp pipe. 15 mm carb. its a fun little bike for sure.

Aaah, I love the smell of testosterone in the morning.

Man cards automatically renewed for anyone in this thread. Hehe.

sine143 wrote:i hit mid 50s on my setup. puch maxi with the polini kit and a proma gp pipe. 15 mm carb. its a fun little bike for sure.

But, I weigh a LOT more than you do, and it makes a big difference. I can tune the transmission and variator weights for a much lighter rider and gain nearly 10 MPH!

Dave Non-Zero wrote:Aaah, I love the smell of testosterone in the morning.

Man cards automatically renewed for anyone in this thread. Hehe.

Thanks, Dave!